Back in the 1950's & 60's it was rare to find station formats defined because the major stations were programming entertainment network shows and filling open time slots with popular music and local shows. It was very standardized block programming. The Broadcasting Yearbooks didn't begin format listings until the early 70's when many stations by then had chosen distinctive formats.
Billboard Magazine, involved in music, saw a need early. In their April 4, 1964 issue they listed Portland Radio Stations with format descriptions. (Billboard arranged order):
KISN 910 - Pop-Contemporary / PD: Don Steele.
KEX 1190 - Pop-Standard / PD: Fulton Wilkins.
KGON 1520 - Contemporary / PD: Sonora B. Hoffman.
KGW 620 - Standard-Pop / PD: Patrick H. Crafton.
KWJJ 1080 - Standard-Jazz-Pop / OM: Jerry Speerstra.
KPOJ 1330 - Standard / PD: Vern Mueller.
KOIN 970 - Standard / GM: Harry H. Buckendahl
KPAM 1410 - Standard-Classical / GM: Del Leeson.
KXL 750 - Conservative-Classical / GM: Lester M. Smith.